1. Field of the Invention
The invention relates to a method for actuating an automated transmission, in particular an automated transmission of a commercial vehicle. The invention also relates to an apparatus for actuating an automated transmission, in particular an automated transmission of a commercial vehicle. The invention, furthermore, covers a test bench which is suitable for a drive motor, in particular a drive motor of a commercial vehicle.
Performance test benches, or testing rigs, are regularly used to test newly developed drive motors, for example of diesel engines. It is possible to simulate and to analyze representative states for the drive motor using a performance test bench of this kind. As a result, certain trials can be performed on the test bench rather than on the road.
However, before a new drive motor can finally be authorized for series production, it is also necessary to test and to optimize the drive motor in terms of its compatibility with an automated transmission which is connected downstream of the drive motor and forms a constituent part of the drive train of the vehicle, in particular commercial vehicle. Both the drive motor and the automated transmission have a respective electronic controller. These controllers interact via at least one interface. An interface of this kind can, but does not have to, meet international standards, for example SAE 1939-71. For the tests and optimizations in respect of interaction between the drive motor and the transmission, applications by trial and comparative trips with a real vehicle are essential and result in relatively high costs. Therefore, with the current prior art, it is not possible to operate an automated manual transmission in, for example, a commercial vehicle without the transmission having to be matched to the drive motor or drive train of the vehicle, and this is complicated.
Patent Application Publication No. US 2008/0275612 A1 and its counterpart German published patent application DE 10 2005 057 809 A1 describe adapting to the respective operating situation in a method for controlling shifting in an automated manual motor vehicle transmission. At the beginning of the shifting process, at least one parameter which characterizes the current operating state of the motor vehicle and/or one shifting parameter which characterizes the provided shifting process is detected and evaluated, and the injection quantity of the drive motor, which injection quantity is associated with the idling torque, is matched to the operating state of the motor vehicle and/or to the shifting process in a variable manner in dependence on the evaluation result.
2. Summary of the Invention
It is accordingly an object of the invention to provide optimizations for the control of an automated transmission which overcome the disadvantages of the heretofore-known devices and methods of this general type and which simplifies and improves the application between a drive motor and an automated transmission in respect of the method and the apparatus. It is a further object to specify a suitable test bench for assisting an application of this kind.
With the foregoing and other objects in view there is provided, in accordance with the invention, a control method for actuating an automated transmission, wherein the transmission is coupled to a drive motor and data and/or signals are supplied to a transmission controller via an interface. The novel method comprises the following steps:
when a defined event occurs, transmitting a temporally predictive non-steady profile of a drive motor torque for the defined event to the transmission controller; and
ascertaining and/or specifying a transmission shifting strategy with the transmission controller on a basis of the data so transmitted to the transmission controller.
In other words, the objects of the invention are achieved with a method for actuating an automated transmission which is coupled to a drive motor, with data and/or signals being supplied to a controller of the automated transmission via an interface. According to the invention, when a defined event occurs, a temporally predictive non-steady profile of the drive motor torque for just this event is transmitted to the controller of the automated transmission, and therefore the transmission controller, that is to say the controller of the automated transmission, ascertains and/or specifies a transmission shifting strategy on the basis of this transmitted data.
The expected (i.e., temporally predictive) profile or structure of the engine torque which is supplied to the transmission controller or the controller of the automated transmission according to the invention constitutes an important basis for a shifting process which is to be carried out in an optimized manner by the transmission controller software. The solution according to the invention considerably simplifies the application between the transmission and the drive motor since only the drive motor torque which can be or is ascertained in a simple manner on a test bench has to be supplied to the transmission or transmission controller as the main variable for the “vehicle force” for defined events. Therefore, a significant portion of the application work can be carried out in a simple manner on the test bench with the solution according to the invention, and therefore expensive trial journeys can be saved.
The non-steady engine torque profile is preferably transmitted and specified in the form of characteristic curves, with the characteristic curves for the respective event being ascertained in an engine-specific manner on a test bench.
A start-up process is preferably considered to be an event. In the simplest case, characteristic curves for at least the drive torque can be derived on the test bench for this event, and therefore, when a start-up process is detected, a temporally predictive non-steady profile of the drive motor torque can be transmitted to the transmission controller, the transmission controller ascertaining and/or specifying a transmission shifting strategy for the start-up process on the basis of the said profile of the drive motor torque.
In this case, the transmission controller advantageously ascertains a start-up rotation speed and/or a start-up gear on the basis of the transmitted profile of the drive motor torque.
Furthermore, an upshifting operation or a downshifting operation of the automated transmission can be considered to be an event. In the simplest case, characteristic curves for at least the drive torque can be derived on the test bench for these events, and therefore, when a shifting process of this kind is detected, a temporally predictive non-steady profile of the drive motor torque can be transmitted to the transmission controller, the transmission controller ascertaining and/or specifying a transmission shifting strategy for the upshifting operation or downshifting operation on the basis of the said profile of the drive motor torque. It is particularly advantageous, for the purpose of monitoring shifting operations and/or for the purpose of avoiding gear hunting, for the transmission controller to ascertain whether a shifting operation, that is to say a shifting process, is to be initiated or not, in particular whether the available torque is sufficient to initiate a shifting operation, that is to say a shifting process, on the basis of the transmitted profile of the drive motor torque, in order to achieve a defined engine behaviour, in particular a defined vehicle acceleration.
Furthermore, a change between overrun operation and traction operation or a drag operation can also be considered to be an event. In the simplest case, characteristic curves for at least the drive torque can be derived on the test bench for these events too, and therefore, when a change between overrun operation and traction operation or a drag operation is detected, a temporally predictive non-steady profile of the drive motor torque can be transmitted to the transmission controller, the transmission controller ascertaining and/or specifying a transmission shifting strategy for the respective change between overrun operation and traction operation or the respective drag operation on the basis of the said profile of the drive motor torque. This can take place, for example, in such a way that the transmission controller ascertains whether a change between overrun operation and traction operation or a change to drag operation is initiated or not on the basis of the transmitted profile of the drive motor torque. The engine brake can then further be switched on in the case of drag operation.
A particularly preferred refinement is one in which the non-steady engine torque profile, that is to say the non-steady profile of the drive motor torque, is specified to the transmission controller in an engine-specific manner as a function of the rating of the respective emissions stage, for example as an SCR emissions stage (SCR=selective catalytic reduction) or as a EURO-VI emissions stage to name just two examples, of the drive motor which is respectively coupled to the automated transmission.
According to a further preferred specific refinement, provision is made for at least the non-steady engine torque profile to be supplied to the transmission controller for defined events by means of a separate control device which is superordinate to the drive motor and to the automated transmission or by means of a separate control device which is coupled to the transmission controller or to the engine controller, at least one event-related engine torque profile being stored in the said control device such that it can be called up.
In addition or, however, primarily as an alternative to the above, provision can also be made, according to a less component-intensive, functionally integral solution, for at least the non-steady engine torque profile to be stored in the engine control device of the respective drive motor for defined events, the said non-steady engine torque profile being transmitted to the transmission controller via the interface when a defined event is detected and occurs.
In conjunction with the two above-mentioned variants, provision can further be made for at least the non-steady engine torque profile for defined events to be transmitted to the transmission controller or a controller for the drive motor by means of an EOL (end of line) programming operation, that is to say a programming operation of the control devices at the end of the assembly line.
It has been found that virtually all the loads on the drive motor which interact with an automated transmission in the commercial vehicle, said loads occurring during actual operation, can be attributed to the events specified above (a start-up process, an upshifting operation and a downshifting operation, a change from overrun operation to traction operation, drag operation) and it can be assumed that the specified events represent the highest requirements in respect of engine dynamics. As long as temporally predictive profiles in respect of the engine torque for the previously presented events can be made accessible to the transmission software, this can also be used in practice for other situations. Furthermore, it is fundamentally also possible to supply other temporally predictive profiles of other technical variables of the drive motor, such as injection quantities, charging pressures or else exhaust gas recirculation (AGR) rate.
With the above and other objects in view there is also provided, in accordance with the invention, an apparatus for controlling an automated transmission which is coupled to a drive motor, especially an apparatus that is configured to carry out the above-summarized method. The novel apparatus comprises:
an interface for supplying data and/or signals to a controller of the automated transmission;
a control device (either integrated in the control apparatus or connected to it and) connected to the interface, the control device holding non-steady and/or dynamic profiles of an engine torque for at least one defined event for forwarding to the controller of the automated transmission.
In other words, the objects of the invention related to the apparatus for actuating an automated transmission, which is coupled to a drive motor, of the kind specified above, are achieved in that an interface is provided, by means of which data and/or signals can be supplied to a controller of the automated transmission. According to the invention, non-steady and/or dynamic profiles of at least the engine torque are implemented for at least one defined event in a control device of the apparatus or in a control device which is coupled to the apparatus, and can be forwarded to the controller of the automated transmission.
A controller of this kind can, as already described above, preferably provide the expected profiles or the profiles, which correspond to a prognosis, of at least the engine torque by means of stored characteristic curves of the typical non-steady and/or dynamic profiles of the engine torque in the case of individual events (for example a start-up process, an upshifting operation or a downshifting operation, a change from overrun operation to traction operation, drag operation) by means of, for example, the conventionally used network CAN (Controller Area Network) of the controller of the automated transmission. This is accompanied in each case by optimization of the shifting process of the automated transmission. The ability to provide other engine variables for prognosis by the transmission controller or the software of said transmission controller is also within the scope of the invention. The implementation of such profiles can be called up in a time-dependent manner, such as by a software counter, by individual data sets which are stored in a one-dimensional or multi-dimensional manner. However, it is also possible to call up and output an obtained formation rule, for example a formula with time dependence.
With the above and other objects in view there is also provided, in accordance with the invention, a test bench for the drive motor in respect of the technical variables of the said drive motor which can be associated with it, in particular also relating to the dynamics thereof. At least one test program is provided in the test bench in order to simulate real loads on the commercial vehicle together with its automated transmission in relation to the drive motor and to make it possible to store and read out at least the time profile of the engine torque in association with the simulated loading events.
Events, preferably a start-up process, an upshifting operation or a downshifting operation, a change from overrun operation to traction operation or a drag operation, can be simulated by the test bench. Only the drive motor which is to be examined, generally a diesel engine in the case of a commercial vehicle, is associated with the test bench. The output shaft of the drive motor is connected in a rotationally fixed manner to an electrical machine, for example a three-phase asynchronous motor, which can be operated in generator mode and/or motor mode. The network of the commercial vehicle is replaced by a corresponding network of the test bench. The controller of the drive motor communicates with the network of the test bench. The time-dependent profiles of technical variables of the drive motor can be detected and stored with each event which is simulated on the test bench. These detected technical variables, in particular the engine torque and, in particular, in respect of the time profile thereof, can therefore be provided for the engine controller such that they can be read out for implementation purposes.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in the optimizations for actuating an automated transmission, in particular an automated transmission of a commercial vehicle, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.